unique background image

Hi - me again :) i want to display a unique background image on one of my pages - now according to all my research this should work.. body.page-id-7534 { background: url('parchment.jpg') no-repeat scroll center top / contain; background-color: #cc0000; } i really don't need the background to be red it just tells me that i'm modifying that page because my image is not appearing there. is there anything in the theme that would prevent me from doing this? is the path to where my images are stored somehow unique? thanks